The purpose of this research is to study the spontaneous and catalytic reactions of highly reactive epoxides in aqueous media. There is evidence that the toxic and carcinogenic nature of certain aromatic hydrocarbons may be linked to their initial conversion to reactive epoxides. Thus benzo(a)pyrene oxide has been isolated as a microsomal metabolite of benzo(a)pyrene, and has been shown to covalently bind to DNA. "K-region" epoxides of other aromatic hydrocarbons such as phenanthrene, 7-methyl- bemz(a)anthracene, and benz(a)anthracene have induced malignant tumors in rats, and also are frameshift mutagens to bacteria. The chemical mechanisms whereby such highly reactive epoxides undergo enzymatic and non-enzymatic reactions therefore become very important. The objective of the proposed research is to carry out a thorough kinetic investigation of catalytic and non-catalytic reactions of epoxides that are either carcinogenic or related in structure to carcinogenic epoxides. Such investigation will shed light on the nature of general acid-catalyzed reactions of epoxides, a mechanism that enzymes can utilize. Product distributions and reaction rates of epoxides will be analyzed as a function of pH. Several papers that we and others have recently published indicate that many reaction pathways are available in the hydrolysis of several highly reactive epoxides. A comparison of the non-enzymatic ractions of epoxides to the enzymatic reactions should lead to some initial insight on the probable mechanisms operating in the enzymatic processes. Kinetic investigations of the reactions of various epoxides can potentially lead to a correlation between carcinogenicity and structure or reactivity of epoxides.